2 8 1 1 P e l l e t P r e s s

The Parr 2811 Pellet Press provides a convenient means for compressing powdered materials into pellet or tablet form without a heavy invest-ment in expensive tablet-making machinery. It is a compact, hand-operated press that can be used anywhere in the laboratory, requiring very little bench space and no fixed mounting, producing uniform pellets in a polished stainless steel die and ejecting them smoothly into a stainless receiver without danger of con-tamination.

For Bomb CalorimetryPellet making is a very

important step in bomb calo-rimetry, particularly when working with finely powdered samples. Although some pow-dered materials burn well in an oxygen bomb, others, such as benzoic acid, must be pellet-ized for safe combustion and best results. There are several advantages to be gained by

burning samples in pellet form instead of a loose powder.

Restricted burning rates. Some materials have dan-

gerously high burning rates if burned as a loose powder. These rates can be restricted to safe levels by compressing the powder into a pellet or briquette.

Complete combustion. Loose powders exposed to

the turbulent gases produced during a bomb combustion may be blown out of the sample cup and extinguished by the cold bomb wall before they have burned completely. A pelletized sample will be held in the combustion zone with a much better chance for com-plete combustion.

Ease of handling. Pelletized samples are easy

to handle and weigh; they lie flat in the combustion capsule and ignite easily.

For Other Test ProceduresPelletized samples are

equally important in other investigative and test proce-dures. Laboratories engaged in pharmaceutical, biological, nutrition and spectrographic operations find frequent uses for tablets and wafers of the types that can be made in a Parr press. Spectroscopists find this device excellent for preparing samples to be ana-lyzed in an emission spectrom-eter. Small diameter pellets made in a Parr pellet press can be imbedded in a hole drilled in the sparking elec-trode, assuring the operator that his sample will always be held in exactly the right posi-tion for best results.

Six Pellet SizesThe pellets produced in

the Parr press are cylindrical in shape with flat ends. Their height or thickness depends upon the amount of mate-rial compressed and the force applied. Six different punch and die sets are available for making pellets in diameters from 3 mm up to a maximum of 1/2 inch. All of these punch and die sets operate in the same basic press. The dies are not fastened down. They automatically align with the punch and may be slipped out from under the punch for quick reloading.

Pressure and Density Adjustments

The compressive force in this press is developed by hand pressure on a lever attached to a large steel cam. This sys-tem is designed to provide a steadily increasing mechani-cal advantage up to a ratio of approximately 50 to 1 at the end of the stroke. Thus, a force of 20 pounds applied to the lever develops approximately 1000 pounds on the punch, which is adequate to produce firm pellets from most pow-dered materials, usually with-out adding a binder.

The anvil which supports the die in the Parr press is attached to a heavy screw post so that it can be raised or lowered. Rotating the anvil to raise or

2811 Pellet Press

2 P a r r I n s t r u m e n t C o m p a n yw w w . p a r r i n s t . c o m

lower the die makes it pos-sible to produce pellets of any desired thickness using the maximum force of the press. When compressing light or fluffy materials the die can be raised after successive punch strokes to compensate for the reduction in the volume of the charge. The variable anvil setting can also be used as a means for adjusting the amount of pressure applied to a pellet. If duplicate pellets of equal den-sity are desired, these can be made by using equal amounts of sample and leaving the anvil at a fixed setting while taking the punch through its full stroke when forming each pellet.

Construction FeaturesThe Parr pellet press is

sturdily constructed with its parts arranged so that they can be easily cleaned and main-tained in good working order. Punches, dies and die plugs in 1/4, 3/8 and 1/2 inch sizes are made of polished T-303 stain-less steel. Any of these indi-vidual parts can be replaced if they become worn or dam-aged, but for the best perfor-mance it is recommended that they be purchased and used in sets. Dies in 1/4 inch and smaller are made of Nitronic 60 material. Punches in 1/4 inch and smaller sizes are made of 17-4 Stainless Steel. Punches are heat treated for added strength and hardness, and then polished to remove the dark oxide layer formed when treated.

Punch and die sets 1/4 inch and smaller are constructed with a 130° angle for ease of loading materials in these small punch and dies.

Pellet Making With A Parr Pellet Press

In four easy steps:1. Fill the die. Set the die and its

holder on the base of the press with the beveled edge of the die resting on the flat surface in the reversible holder. Pour the charge into the die cavity and tamp with a stirring rod, if necessary.

2. Compress the charge. Transfer the die and its holder to the press and push the lever down to compress the charge. To obtain maximum compression, the lever should require a firm push as it moves through its full stroke. If a full stroke is not obtained, turn the anvil to lower the die until the full mechanical advan-tage of the press can be utilized. Convers ely, if the lever moves through its full stroke without encountering sufficient resistance, raise the die until firm compres-sion can be applied.

3. Reverse the die holder. Raise the lever and slide the die and its holder out of the press. Reverse the holder to bring the deep cavity under the die and return the parts to their original position. The clearance under the punch will be limited when making thin pellets. In such cases it will be more convenient to grasp the die with one hand and slide it upward on the punch, holding it in that position while reversing the die holder with the other hand.

4. Eject the pellet. Bring the lever down gently to eject the pellet into the cavity in the holder. If a thick pellet is not ejected by this stroke, turn the anvil to raise the die. The pellet will then drop out freely. Remove the pellet with tweezers or forceps; reverse the holder and repeat the cycle if additional pellets are required.

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2 8 1 1 P e l l e t P r e s s

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Dimensions & Weights

Ordering Guide

211 53rd StreetMoline, Illinois 61265 USAPhone: 1-309-762-7716 or 1-800-872-7720Fax: 1-309-762-9453E-mail: parr@parrinst.comhttp://www.parrinst.com

Length of lever arm 7 in.Maximum punch stroke 1.25 in.Depth of cavity in: .50 and .375 inch dies 1 in. .25, .125 and metric dies 0.75 in.Dimensions of press base 5 x 9 in.Overall press height 10 in.Weight of assembled press 17 lb.Gross shipping weight 20 lb.

Size of Punch Model No. & Die Set 2810 Pellet Press None 2811 Pellet Press 0.50 in. 2813 Pellet Press 0.375 in. 2817 Pellet Press 0.25 in. 2818 Pellet Press 0.125 in. 2819 Pellet Press 3.0 mm 2820 Pellet Press 4.5 mm

Extra Punch and Die Sets* Size of Punch Model No. & Die Set A51PR 0.50 in. diameter A51PR3 0.375 in. diameter A51PR12 0.25 in. diameter, 130˚ A51PR13 0.125 in. diameter, 130˚ A51PR14 3 mm diameter, 130˚ A51PR15 4.5 mm diameter, 130˚

Pellet Press Replacement Parts

40PR2 Die Holder (Used in all current pellet press models*)

A51PR & A51PR3Punch & Die Sets 1/2 in. and 3/8 in.

A51PR8 - A51PR11(82 degree taper) Punch and Die Sets 1/4 in., 1/8 in., 3 mm, and 4.5 mm

A51PR12 - A51PR15(130 degree taper) Punch and Die Sets 1/4 in., 1/8 in., 3 mm, and 4.5 mm

40PR2Die Holder

* These punch and die sets include the bolt and washer or fastener for the punch, but no die holder. A 40PR2 die holder must be added when using any of these sets to replace the A33PR punch and die arrangement used in earlier models of the Parr press.

A51PR, & A51PR3

A51PR8 ~ A51PR11 A51PR12 ~ A51PR15 40PR2

A51PR, & A51PR3

A51PR8 ~ A51PR11 A51PR12 ~ A51PR15 40PR2

A51PR, & A51PR3

A51PR8 ~ A51PR11 A51PR12 ~ A51PR15 40PR2

A51PR, & A51PR3

A51PR8 ~ A51PR11 A51PR12 ~ A51PR15 40PR2

Bulletin 2811 500 0715 Printed in USA